Preservative composition



Patentedpec. .1942

{UNITED s'r Es- PATENT" crime Y PRESERVATIVE COMPOSITION Frederick H.Norton, Midland,-Mich., assignor to .1 g

The Dow Chemical Company, Midland,

a corporation of Michigan Mich,

.N'o Drawing. Application March 27, 1941, jv

-. Serial No. 385,473 j 12 Claims. (o1.1s7-.-ss.7)

This invention relates to preservative compositions and is particularlyconcerned with liquid concentrates comprising chloro-phenols and triarylphosphates and adapted to be; dissolved in petroleum distillate or othersuitable solvent to form wood treatment solutions.

The treatment of wood products with synthetic organic chemicals toprovide protection against fungi, borer, and termite attack is commonpractice. 'In many instances the active toxicant is dissolved in arelatively volatile organic solvent and the wooden article dipped inor'imp regnatedwith the treating solution. When a crystalline toxicantis employed,the subsequent evaporationof the solvent frequently leaves avisible residue or bloom of crystalline'preservative which isobjectionable in appearance, toxic tothose handling the treatedarticles, and readily dusted from the treated surface.

The chloro phenols are widely employedin the treatment. of such woodenproducts as sash, finish lumber, trim, and the like. as a class arerelatively high-melting products and some, such as pentachloro-phenol,tetrachloro-phenol, trichloro-phenol, and the like,

tend to sublimef When such compounds are employed in volatile-base woodtreatment compositions, crystalline residues are left upon the surfacestreated. 'Furthermore, even though deposited'substantially below thetreated surface by ;-f

impregnation, these compounds sublime out and crystallize on the surfaceto form objectionable residues. A further disadvantage in the use ofthesephenolic derivatives resides in the difficulty encountered inpreparing solutions thereof in z;

the solvents common to the wood treating art. Thus, it is frequentlynecessary to heat these phenols with volatile, explosive, and flammableorganic carriers, such as petroleum naphtha, in

order to accomplish solution. "This practice constitutes a -hazard whichmaterially limits the extrichloro-phenol, 2.4.5-trichloro phenol, I and2- phenyl.-4-'chloro-pheno1. Preferred phosphates are triphenylphosphate and tricresyl phosphate, although other related compounds maybefused.

A non-blooming composition miscible with "such 3 by weight of triphenylphosphate and 100 parts of pent'achloro-phenol gives concentrates havingthe desireds olubility andariti-blo'ojm 'charac The ch'loro-phenols 7form clear homogeneous solutions whichrem'ain free flowing and mobile oncooling. Such a content-to which the chloro-phenols are employedin woodtreatment. I e

According to the present invention the fore-' going disadvantages areobviated by dissolving the solid chlorophenol or mixture ofchloro-phenols in a triarylphosphate to form a liquid concentrate. Suchconcentrate is more readily soluble in hydrocarbon and wood tar oilsthan the chloro-phenol alone and in many instances is miscible in allproportions with the petroleum distillates commonly employed in woodtreating. The phenolic residues from treatment with dilute solutions ofsuchtconcentrates have been found 7 not to bloom on wooden surfaces andto be uriusually effective in the control of wood parasites.

The solid chloro-phenols whichhave been found particularly valuable inthe compositions with which the present invention is concerned arepentachloro-phenol, 2.3.4.6-tetrachloro-phenol, 2.4.6-

teristics' and melting at 20C. or lower.

by weight of phosphate per' 100 parts of phenol are required. With 100parts of 2-phenyl-4-chloro-phenol, 190 parts orhigher of the phosphateare required. When mixtures of two or more of the chloro-phenolsareemployed, the amounts of phosphate required vary over wide ranges butV are generally somewhat lower than when a single phenol is concerned.Concentrates of much lower freezing point are obtainable when such mixedphenols are employed, and this modification of the invention constitutesa p ferred embo iment.- v

In preparing the new concentrates, the, re-

quired amounts of chloro-phenol and' triaryl" phosphate are warmedtogether and stirred to centrate may be diluted with any suitablemiscible solvent to obtain treating compositions,

preferably comprising from 1 to 10 per cent of the phenolic constituent.While not essential, other germicidal and fungicidal materials may beIn-' corporated with the concentrate. aswcllas or-- ganic solvents, suchas diacetone alcohol, methyl ethyl ketone, and the like.

The following examples are not to be construed as limiting theinvention:

EXAMPLE 1 i 2.5 parts by weight of mixed 2-phenyl-monochloro-phenols,1.5 parts of penta'chlorophenol;:

1 part of 23.4.6-tetrachloro-phencl. and 2'parts of triphenyl phosphatewere warmed together to obtain a liquid concentrate which was cooled to.

below 5 C. without freezing or depositing crys-' tals. v7 parts byweight otthis concentrate'was stirred into 93 parts by weight of apetroleum d stillate boiling at 233 360 F. and having a flash point bythe closed cup method of 82 F.

Simi- I larly, from 100 to 170*pa'rts by weight of the phosphatedissolve 100 parts of 2.'3. l.6-tetrachloro-phenol to formflsatisfactorycompositions. With 2.416-trichloro-phenol, from 85 to 200 parts Theconcentrate passed into solution readily without heating to form a cleartreating product containing per cent by weight of phenolic constituents.Samples of window sash were immersed in this productfor 3' minutes andthereafter and insect attack.

EXAMPLE 2 4 parts by weight of pentachloro-phenol, 2 parts of2.3.4.6-tetrachloro-phenol, and 0.25 part 'Ihiscompositionhas a freezingpoint 0120 C. or lower.

' Composition, 5

I Parts by weight 2.3.4.6-tetrachloro-phenol 3"! Triphenyi phosphate 63This composition has a freezing point of C.

or lower.

1 Composition 6 I I 'Partsby weight v I 2.4.5-trichloro-phenol 57Triphenyl phosphate 43 of 2.4.6-trichloro-phenol were fused togetherwithv stirring. 51 parts by weight of this mixture was warmed andstirred with 49 parts of triphenyl phosphate to obtain a liquidpreservative .concentrate which was cooled to 0 C. without depositingcrystalsf This composition was adapted to be diluted with' petroleumdistillate to produce a solution for dipping wooden articlessubstantially as described in Example 1.

EXAMPLE 3 below 20 C. without freezing or depositing crystals. 86 partsof this phenolmixture melted andstirr'ed with .14 parts of triphenylphosphate.

gave a concentrate having a freezing point of 20 C. or lower. 38 partsof the phenol mixture compounded with 62 part of tri'phenyl phosphatealso gave a concentrate freezing at 20 C. or lower. Each of these liquidconcentrates was adapted to be employed in the preparation ofnon-blooming wood treating solutions substantially as described inExample. 1.

EXAMPLE 4 In a similar manner other solid; chloro-phenols and phenolmixtures were dissolved in triaryl phosphates to obtain. liquidpreservative com-- positions of .which the following are representative:i

I Composition 1 I Parts by weight Pentachloro-phenyl 40 Triphenylphosphate' 60 I This composition has a freezing point of 20 C. or lower.

Composition 2 Parts by weight Penetachloro-phenol 33 Triphenyl phosphate-67 This composition has a'freezing point'of 20 C. or lower.

Composition 3 Parts by weight Pentachloro-phenol 47 Tricresyl phosphate53 I Weight-$- 35 2.4.6-trichloro-phenol Triphenylphosphate (stillresidue) 55 This composition was cooleditobelow -15 C. withoutdepositing crystals. i I 40 II Composition 10 i I Parts by weight2-phenyl-4-chloro-phenol 8 2-phenyl-6-chloro-phenol. '32 4r) Triphenylphosphate II This composition was-cooled to below 20,; C. s. withoutdepositing crystals. I

Compositton'fl Parts by weight 2-phenyl-4-chloro-ophenol c 34"'Triphenyl phosphate ...-z 66 This composition has'a freezing point of20 C. 55 or lower;

Composition 12 I weight j Partsbyi I 2-phenyl-4-chloro-phenoi. 29 60'I'riphenyl phosphate 71:,

This composition has a freezing point of 20C. or lower.

Composition 7 f i I II Parts'b'y I f weight 2.4.6-trichloro-phenol 54Triphenyl phosphate 16"] This composition has a, freezing point of 20 C.or lower. j o

- f-Compositioni 1 -Partsby 1;

weight, 2.4.6-trichloro-phenol 33 Triphenyl phosphate j' 67 Thiscomposition has a freezing point of20" c. i

or lower.

Composition .9

. I or lower.

This composition was cooled to below 10 C. without depositing crystals.

Composition 4 I Parts by weight 2.3.4.6-tetrachloro-phenol e 50Triphenyl phosphate 50 Each of the foregoing compositionsis'liquid attemperatures above 20 C. and isre'adily. soluble in the organic solventscommonly employed in i wood dipping and impregnation. These concen-ttrates, when diluted with such solvents, may be employed for treatingwood or wooden articles. The treated and dried surfaces ,soobtainedareprotected against attack by fungi and insects and 1 do not bloom.

Other triaryl phosphateswhich I may be 'employed substantially as setforth above arediphenyl-2-xenyl phosphate, di- (2.-xenyl) -phenyl.phosjI phate, (5-tertiarybutyl-2 irenyl) -di- (l-tertiary? .Parts'bybutyl-phenyl) phosphate, cliphenyl-(2-chlorophenyl) phosphate,dicresyl-(2-ohloro-phenyl) phosphate, dicresyl-phenyl phosphate, etc.

I claim:

1. A wood preservative comprising a solid chloro-phenol dissolved insufficient of a triaryl phosphate that the freezing point of thephenolphosphate solution is below 20 C.

2. A liquid preservative concentrate comprising as a major constituent asolution of a solid chloro-phenol in sufficient of a triaryl phosphatethat the freezing point of the solution is below, 20 C.

3. A wood preservative comprising a solid chloro-phenol dissolved insufficient triphenyl phosphate that the freezing point of thephenolphosphate solution is below 20 C.

4. A liquid preservative concentrate comprising as a major constituent asolution of a solid chloro-phenol in suflicient triphenyl phosphate thatthe freezing point of the solution is below 20 C.

5. A wood preservative comprising a member of the group consisting ofpentachloro-phenol, 2.3.4.6-tetrachloral-phenol, 2.4.5trichloro-phenol,2.4.6-trichloro-phenol, and, 2-phenyl-4-ch1orophate that the freezingpoint of the solution is phenol dissolved in suffioient of a triarylphos- 2.3.4.G-tetrachloro-phenol, 2.4.5-trich1oro-phenol,

2.4.6-trichloro-phenol, and 2-phenyl-4-chlorophenoldissolved insufiicient of a triaryl phos- 8. A liquid preservative concentratecomprising as a major constituent a solution of a member of the groupconsisting of pentachloro-phenol,

2.3.4.6-tetrachloro-phenol, 2.4.5-trichloro-pheno1,2.4.6-trichloro-phenol; and 2-phenyl-4-cholorophenol dissolved insufllcient triphenyl phosphate that the freezing point of the solutionis below 20 C.

9. A wood preservative comprising a mixture 10. A wood preservativecomprising a'mixture of at least two of the group consisting ofpentachloro-phenol, 2.3.4.6-tetrachloro-phenol, 2.4.5- trichloro-phenol,2.4.6-trich1oro-phenol, and 2- phenyl-4-chloro-phenol dissolved insufficient triphenyl phosphate'that the freezing point of thephenol-phosphate solution is below 20 C.

11. A liquid preservative concentrate comprising as a major constituenta solution of at least two of the group consisting ofpentachloro-phenol, 2.4.5.6-tetrachloro-phenol, 2.4.5-trichloro-phenol,2.4.6-trichloro-phenol, and 2-phenyl-4-chlorophenol dissolved insufficient of a triaryl phosphate that the freezing point 'of theresulting composition is below 20 C.

12. A liquid preservative concentrate comprising as a major constituenta solution of at least two of the group consisting of pentachloroFREDERICK H. NORTON. I

